Antioxidant compositions useful in biodiesel and other fatty acid and acid ester compositions

ABSTRACT

Compositions containing phenolic antioxidant solutions are provided. The invention further provides methods of making and using such compositions as well as compositions that contain both biodiesel and at least one antioxidant concentrate solutions and blended fuel compositions containing biodiesel blended with other fuels.

CROSS REFERENCE TO RELATED APPLICATIONS

Priority is claimed to U.S. Provisional Application No. 60/764,997,filed Feb. 3, 2006 and to U.S. Provisional Application No. 60/857,272,filed Nov. 7, 2006.

FIELD OF THE INVENTION

The present invention relates to compositions and methods involvingantioxidant formulations that are suitable for use in fatty acid andfatty acid ester compositions such as those used in the food and/or fuelindustries.

DESCRIPTION OF RELATED ART

Animal fats, such as edible-grade lard and tallow, and vegetable oils,such as sunflower, rapeseed, soybean, corn, palm and coconut oils, havefound widespread use in the food industry. Recently, the use of virginand reclaimed animal fats and vegetable oils as an alternative energysource, such as use of esterified fatty acids in biodiesel, has beeninvestigated. One problem associated with the use of these materials istheir susceptibility to oxidation. Such oxidation can result indecomposition of unsaturated fatty acid esters into undesirablecompounds. The decomposition can lead to precipitation and formation ofmaterials that can cause problems with engine parts such as injectionsystems, pumps and nozzles of the diesel engines as well as incompletecombustion and increased soot formation. Protecting the fuel quality ofbiodiesel and its blends with petroleum diesel during long term storageis desirable for manufacturers, blenders, suppliers, and users.

The use of antioxidants in biodiesel has therefore been considered.Various formulations containing phenolic antioxidant compounds such asbutylated hydroxyanisole (BHA), as 2,6-di-tert-butylphenol,2,6-di-tert-butyl-4-methylphenol (BHT) and tert-butylhydroquinone (TBHQ)have been examined for their ability to reduce or slow oxidation. Acommon method for incorporating antioxidants into biodiesel is in asolution form. However, finding solvents that will carry higherconcentrations of phenolic antioxidants along with other additives,while being miscible with biodiesel, is a challenge. There is acontinued need for new concentrated formulated antioxidants in solutionform for biodiesel stabilization.

SUMMARY OF THE INVENTION

The present invention provides compositions useful as antioxidantconcentrate solutions. The compositions contain at least one phenolicantioxidant, at least one metal chelating compound and at least onesolvent. It has been found that selection of the proper components ormethods of preparation allows preparation of solutions that contain highconcentrations of phenolic antioxidants while also dissolving a metalchelating agent and being miscible with biodiesel. In some embodiments,it has been found that selecting the proper order in which to combinethe components can improve the ability to achieve higher concentrationsof phenolic antioxidants when used in connection with metal chelatingcompounds. Thus, the invention further includes methods of making theconcentrate solutions. The invention further includes biodiesel fuelcompositions that contain the concentrate solutions of the presentinvention as well as fuel compositions comprising biodiesel as well asother burnable sources such as petroleum diesel. The invention furtherincludes methods of using the antioxidant concentrate solutions of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Compositions containing phenolic antioxidant solutions are provided. Theinvention further provides methods of making and using such compositionsas well as compositions that contain both biodiesel and at least oneantioxidant concentrate solution and blended fuel compositionscontaining biodiesel blended with other fuels. In some cases, forexample, difficulties arise in dissolving citric acid in solvents thatcan dissolve high concentrations of antioxidant to form a solution thatis readily miscible in biodiesel. The invention overcomes this problemin many ways. For example, in some embodiments, the invention provides aproper solvent or combination of solvents that will allow achievinghigher concentrations than previously achieved. In some embodiments, theinvention provides alternate metal chelating compounds having morecompatible solubility than citric acid. In some embodiments, theinvention provides single solvent or solvent matrices that allow higherconcentrations to be achieved. In some embodiments, the components arecombined in a specific order that has been found to allow higherconcentrations to be achieved.

Biodiesel

As used throughout this application, “biodiesel” shall mean compositionsthat contain at least about 50% by weight of esters of saturated andunsaturated fatty acids that can be used as biodiesel fuel for dieselengines. In some embodiments, the biodiesel contains higherconcentrations by weight of the esters, with examples being at leastabout 60%, at least about 70%, at least about 80% at least about 90%, atleast about 95%, or at least about 99%, in each case the percentagesbeing by weight. In some embodiments the esters are methyl esters, ethylesters, or propyl esters of fatty acids, or combinations of two or morethereof. In some embodiments the esters are methyl esters of fattyacids. In some embodiments, the fatty acid esters in biodiesel are oneor more C₁₄ to C₂₄ fatty acid methyl esters, where C₁₄ to C₂₄ refers tothe number of carbons bonded to the methyl group by the ester linkage.

Antioxidant Concentrate Solutions

The invention provides antioxidant concentrate solutions, which arecompositions containing concentrated phenolic antioxidants for deliveryinto biodiesel. The compositions include at least one phenolicantioxidant and at least one solvent or combination of solvents andoptionally other components. Metal chelating compounds are examples ofadditional components. Thus, in some embodiments the compositioncomprises at least one phenolic antioxidant compound, at least one metalchelating compound, and at least one solvent. Other components may alsobe present.

Phenolic Antioxidant

As used throughout this application, “phenolic antioxidants” or“antioxidants” shall mean compounds that slow oxidation of fatty acidesters selected from: phenol compounds, bisphenol compounds, diphenolcompounds, diphenol monoether compounds and triphenol compounds. Someexamples of phenol compounds having antioxidant activity include mono,di, and trialkylated phenols such as 2,6-di-tert-butylphenol,2,4-di-tert-butylphenol, and 2,6-di-tert-butyl-4-methylphenol (BHT).Some examples of bisphenol compounds having antioxidant activity include2,2′-methylene-bis-(4-methyl-6-tert-butylphenol) (BKF) and2,2′-methylene-bis-(4-methyl-6-cyclohexylphenol). Some examples ofdiphenol compounds having antioxidant activity include hydroquinone(HQ), mono and dialkylated hydroquinones having one or two C₁-C₈ alkylgroups (e.g. tert-butylhydroquinone (TBHQ),2,5-di-tert-butylhydroquinone (DTBHQ), methylhydroquinone (also knownas. 2-methylhydroquinone, toluhydroquinone or THQ),2,5-di-tert.-octylhydroquinone (DOH)), catechol (also known aspyrocatechol) and mono and dialkylated catechols having one or two C₁-C₈alkyl groups (e.g. tert-butylcatechol). As used throughout thisapplication, references to “C₁-C8 alkyl groups” refers to alkyl groupsthat possess one to eight carbon atoms. In some embodiments, thediphenol compound selected is TBHQ. Some examples of diphenol monoethercompounds having antioxidant activity include 4-methoxyphenol(hydroquinone monomethyl ether, or HQMME)) and 2-methoxyphenol(guaiacol, or catechol monomethyl ether), butylated hydroxyanisole(BHA). Some examples of triphenol compounds having antioxidant activityinclude pyrogallol (1,2,3-trihydroxybenzene) and C₁-C₁₈ esters of gallicacid such as n-propyl gallate. In some embodiments, at least onetriphenol compound is a C₁-C₈ ester of gallic acid. In some embodiments,at least one triphenol compounds is pyrogallol.

As used throughout this application, references to carbon numbers inconnection with alkyl groups (e.g. “C₁-C₈ alkyl groups”) refers to alkylgroups that possess the number of carbon atoms referred to (one to eightcarbon atoms in the example given). As used throughout this application,“alkyl groups” shall refer to saturated, unsubstituted groups containingone or more carbon atoms along with hydrogen atoms. Alkyl groups may bebranched or unbranched.

In some embodiments, the phenolic antioxidant is selected fromdiphenols, triphenols and bisphenols. In some embodiments, the phenolicantioxidant is selected from the diphenols described above, or acombination thereof. In some embodiments, at least one of the diphenolsis TBHQ. In some embodiments, at least one of the diphenols is catecholor a mono and dialkylated catechol having one or two C₁-C₁₆ alkylgroups. In some embodiments, at least one of the diphenols is t-butylcatechol. In some embodiments, at least one phenolic antioxidant isselected from the triphenols described above. In some embodiments, atleast one phenolic antioxidant is pyrogallol. In some embodiments, atleast one phenolic antioxidant is selected from TBHQ, t-butyl catecholand pyrogallol. In some embodiments, at least one phenolic antioxidantis selected from the bisphenols described above, or a combinationthereof. In some embodiments, at least one phenolic antioxidant is BKF.Embodiments exist that include a single phenolic antioxidant, whileothers contain a combination of two or more phenolic antioxidants.

Metal Chelating Compound

As used throughout this application, the terms “metal chelatingcompound,” “metal chelator” and “chelator” shall all mean any compoundsthat will chelate metal cations present in biodiesel. The addition ofmetal chelating compounds to phenolic antioxidants further increases theoxidative stability of biodiesel. Any suitable metal chelator may beused and many chelators are known in the art. Some examples include:hydroxycarboxylic acid chelators, such as citric acid; hydroxycarboxylicacid ester chelators such as triethyl citrate and monostearyl citrate;Schiff Bases such as N,N-disalicylidene-1,2-propanediamine, (DMD);aminoalcohols such as triethanolamine and N-hydroxyethylethylenediamine;polyamines such as ethylenediamine and diethylenetriamine; andaminocarboxylic acid chelators such as ethylenediaminetetraacetic acid(EDTA). Mixtures of metal chelating compounds can also be used. In someembodiments, at least one metal chelator is selected fromhydroxycarboxylic acid ester chelators, hydroxycarboxylic acid esterchelators, Schiff Bases, aminoalcohols, polyamines and aminocarboxylicacid chelators. In some embodiments, at least one metal chelator isselected from one or more of the preceding examples or groups ofexamples. In some embodiments, at least one metal chelating compound isa hydroxycarboxylic acid ester chelator. In some embodiments, at leastone metal chelating compound is a hydroxycarboxylic acid chelator. Insome embodiments, at least one metal chelating compound is anaminoalcohol. In some embodiments, the metal chelating compound is apolyamine. In some embodiments, at least one metal chelating compound iscitric acid. In some embodiments, at least one metal chelating compoundis triethyl citrate. Embodiments exist that include a single metalchelating compounds, while others contain a combination of two or moremetal chelating compounds.

Solvents

The solvents of the present invention may be a single compound or acombination of solvent compounds, such as in a solvent matrix. In someembodiments, the solvents are selected from monofunctional alcohols,glycols, polyols, esters, ethers, glycol ether acetates, ketones, glycolethers, amides, nitro compounds and combinations of two or more of theforegoing. In some embodiments, the solvent is liquid at standardtemperature and pressure.

In some embodiments, at least one of the solvent compounds is amonofunctional alcohol. Some examples of monofunctional alcohols includeC₁-C₂₅ monofunctional alcohols, but also include monofunctional alcoholsselected from smaller ranges such as C₂-C₂₅ alcohols, C₂-C₁₀ alcohols,C₃-C₁₀alcohols, C₃-C₁₈ alcohols, C₈-C₁₈ alcohols, and so forth. Someexamples of C₃-C₁₈ monofunctional alcohols include n-propyl alcohol,isopropyl alcohol, n-butyl alcohol, amyl alcohol, 2-ethyl hexanol, decylalcohol, and 1-octadecanol. As used throughout this application,references to compounds as having a specific number of carbon atoms(e.g. “C₂-C₁₀”) refers to compounds for which the total number of carbonatoms in the molecule is in the range specified (e.g. 2-10 totalcarbons).

In some embodiments, at least one of the solvent compounds is a polyol.Some examples of polyol solvents include glycols such as ethyleneglycol, polyethylene glycol, propylene glycol, diethylene glycol,dipropylene glycol, triethylene glycol, tripropylene glycol. In someembodiments, the polyol used is propylene glycol.

In some embodiments, at least one of the solvent compounds is a glycolether. As used throughout this application, a “glycol ether” shall meanto a molecule having the structure of a glycol except that the moleculepossesses an ether linkage to an alkyl group instead of one of thehydroxyl groups. Thus a monoalkyl ether of ethylene glycol, for example,has the structure of ethylene glycol with an ether linkage connected toan alkyl group instead of one of the two hydroxyl groups normally foundon ethylene glycol. By way of further example, “ethylene glycol monobutyl ether” refers to a molecule having the structure of ethyleneglycol with an ether linkage connected to a butyl group. Further, areference to a number of carbons on the ether refers to the number ofcarbons in an alkyl group attached to the ether linkage. Thus, a “C₃-C₁₀glycol ether” refers to a glycol ether in which alkyl group attached tothe ether has three to ten carbons.

In some embodiments, the glycol ether solvent includes 1-3 etherlinkages and exactly one hydroxy (—OH) group. Some examples includeC₁-C₁₂ monoalkyl ethers of ethylene glycol, C₁-C₁₂ monoalkyl ethers ofdiethylene glycol, C₁-C₁₂ monoalkyl ethers of triethylene glycol, C₁-C₁₂monoalkyl ethers of propylene glycol, C₁-C₁₂ monoalkyl ethers ofdipropylene glycol, and C₁-C₁₂ monoalkyl ethers of tripropylene glycol.Examples include ethylene glycol monopropyl ether (available as EastmanEP Solvent from Eastman Chemical Company, Kingsport Tenn., USA),ethylene glycol monobutyl ether, ethylene glycol monohexyl ether,ethylene glycol mono-2-ethylhexyl ether, diethylene glycol monomethylether, diethylene glycol monoethyl ether, diethylene glycol monopropylether, diethylene glycol monobutyl ether (available as Eastman DBSolvent from Eastman Chemical Company, Kingsport Tenn., USA), propyleneglycol monomethyl ether, propylene glycol monoethyl ether, propyleneglycol monopropyl ether, propylene glycol monobutyl ether, dipropyleneglycol monomethyl ether, dipropylene glycol monoethyl ether, dipropyleneglycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, andcombinations of two or more thereof. In some embodiments, the glycolether is selected from diethylene glycol monobutyl ether and ethyleneglycol monopropyl ether.

In some embodiments, at least one of the solvent compounds is an ester.Examples of ester solvents include C₃-C₂₄ esters (wherein C₃-C₂₄ refersto the number of carbon atoms on the larger of the two groups of carbonatoms on either side of the ester linkage; the groups may be branched,unbranched, saturated or unsaturated). Some examples of ester solventsinclude methyl acetate, ethyl acetate, n-propyl acetate, isopropylacetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate, amylacetate, methyl amyl acetate, n-propyl propionate, n-butyl propionate,isobutyl isobutyrate, 2-ethylhexyl acetate, ethylene glycol diacetate,dimethyl adipate, dimethyl succinate, dimethyl glutarate, C₁₂-C₂₄ fattyacid methyl esters, propylene glycol diacetate (diacetoxypropane), andcombinations of two or more thereof. In some embodiments, the estersolvent is a C₃-C₁₅ compound.

In some embodiments, at least one of the solvent compounds is a glycolether ester compound. In some embodiments, the glycol ether estercompound is a C₁-C₁₂ glycol ether ester compound, in which C₁-C₁₂ refersto the number of carbons in the alkyl group attached to the etherlinkage. Glycol ether esters have structures similar to glycol ethersexcept that they possess an ester linkage in the place of the hydroxygroup on the corresponding glycol ether. Thus, for example, ethyleneglycol monobutyl ether acetate, has the structure of ethylene glycolmonobutyl ether with an acetate group substituted for the hydroxy group.Some examples include acetate esters of C₁-C₁₂ monoalkyl ethers ofethylene glycol, the acetate esters of C₁-C₁₂ monoalkyl ethers ofdiethylene glycol, the acetate esters of C₁-C₁₂ monoalkyl ethers oftriethylene glycol, the acetate esters of C₁-C₁₂ monoalkyl ethers ofpropylene glycol, the acetate esters of C₁-C₁₂ monoalkyl ethers ofdipropylene glycol, and the acetate esters of C₁-C₁₂ monoalkyl ethers oftripropylene glycol. More specific examples includeethyl-3-ethoxypropionate, ethylene glycol monobutyl ether acetate,ethylene glycol monoethyl ether acetate, propylene glycol monoethylether acetate, propylene glycol monomethyl ether acetate, diethyleneglycol monoethyl ether acetate, diethylene glycol monobutyl etheracetate, dipropylene glycol monomethyl ether acetate, and combinationsof two or more thereof.

In some embodiments, at least one of the solvent compounds is an ethercompound. Some examples of solvents selected from the class of ethersinclude diisopropyl ether, tetrahydofuran (THF), dipropylene glycoldimethyl ether, and combinations of two or more thereof. In someembodiments, the ether is THF.

In some embodiments, at least one of the solvent compounds is a ketone.Some examples of solvents selected from the class of ketones includestraight or branched C₃-C₁₄ ketones (wherein C₃-C₁₄ refers to the numberof carbon atoms in the ketone molecule). In some embodiments, ketonesare selected from acetone, methyl ethyl ketone, methyl propyl ketone,methyl isobutyl ketone, methyl isoamyl ketone, cyclohexanone, methylamyl ketone, and combinations of two or more thereof.

In some embodiments, at least one of the solvent compounds is an amidecompound. In some embodiments, the amide is a C₂-C₁₀ amide (whereinC₂-C₁₀ refers to the number of carbon atoms in the ketone molecule).Some examples of solvents selected from the class of amides includeN,N-dimethylformamide (DMF), N-methylpyrrolidone and dimethylacetamideand combinations of two or more thereof. In some embodiments, the amideis DMF.

In some embodiments, at least one of the solvent compounds is a nitrocompound. Some examples of solvents selected from the class of nitrocompounds include nitropropane isomers, nitrobenzene and combinations oftwo or more thereof.

In some embodiments, the solvent is a single solvent compound selectedfrom one of the C₁-C₁₂ glycol ethers, C₂-C₁₀ amides, C₃-C₁₄ ketones,C₂-C₁₀ ethers, C₃-C₂₅ esters, polyols, and one of the above groups ofalcohols (e.g. C₂-C₂₄ alcohols or C₃-C₁₈ alcohols). In some embodiments,the solvent is a single solvent selected from one of the C₂-C₁₅ glycolethers, C₂-C₁₀ amides, C₃-C₁₄ ketones, C₂-C₁₀ ethers, C₃-C₁₅ esters,polyols, and one of the above groups of alcohols (e.g. C₂-C₂₄ alcoholsor C₃-C₁₈ alcohols). In some embodiments, the single solvent compound isselected from glycol ethers, alcohols, and amides. In some embodiments,the single solvent compound is selected from glycol ethers and alcohols.In some embodiments, the single solvent compound is selected fromethylene glycol monopropyl ether, diethylene glycol monobutyl ether,ethanol, isopropanol, and DMF. In some embodiments, the single solventcompound is selected from ethylene glycol monopropyl ether anddiethylene glycol monobutyl ether. In some embodiments the singlesolvent compound is selected from glycol ethers, alcohols, ethers,ketones, amides and esters. In some embodiments the single solventcompound is selected from amides, ketones, esters.

In some embodiments, the solvent includes a combination of two or morecompounds. In some embodiments, the solvent compounds include at leastone glycol ether and at least one glycol, wherein the glycol is presentat a concentration of at least about 7% weight percent based on thetotal weight of the total antioxidant concentrate composition. In someembodiments, the compounds include at least one ester compound and atleast one glycol, wherein the glycol is present at a concentration of atleast about 7% weight percent based on the total weight of the totalantioxidant concentrate composition. In some embodiments, the compoundsinclude at least one ester compound and at least one alcohol, whereinthe alcohol is present at a concentration of at least about 7% weightpercent based on the total weight of the total antioxidant concentratecomposition. In some embodiments, the compounds include at least oneketone and at least one glycol, wherein the glycol is present at aconcentration of at least about 7% weight percent based on the totalweight of the total antioxidant concentrate composition.

Any useful combination can be selected. In some embodiments of thepresent invention the solvent mixture contains from about 25 to about 45weight % of an ester, from about 45 to about 65 weight % of a glycolether, and from about 1 to about 20 weight % of a polyol, wherein thesolvent weight percentages are based on the total weight of allsolvents. In some embodiments of the present invention the solventmixture contains from about 30 to about 40 weight % of an ester, fromabout 50 to about 60 weight % of a glycol ether, and from about 5 toabout 15 weight % of a glycol, wherein the solvent weight percentagesare based on the total weight of all solvents. In some such embodiments,the ester is selected from methyl acetate, ethyl acetate, n-propylacetate, isopropyl acetate, n-butyl acetate, isobutyl acetate,tert-butyl acetate, propylene glycol diacetate and combinations of twoor more thereof; the glycol ether solvent is selected from ethyleneglycol monopropyl ether, ethylene glycol monobutyl ether, ethyleneglycol mono-2-ethylhexyl ether, diethylene glycol monomethyl ether,diethylene glycol monoethyl ether, diethylene glycol monopropyl ether,diethylene glycol monobutyl ether, propylene glycol monomethyl ether,dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether,and combinations of two or more thereof; and from the polyol solventselected from ethylene glycol, polyethylene glycol, propylene glycol,diethylene glycol, dipropylene glycol and combinations of two or morethereof. In some of the foregoing embodiments, the ester is n-butylacetate, the glycol ether is diethylene glycol monobutyl ether and thepolyol is propylene glycol.

In some embodiments, the solvent includes a single solvent compoundselected from ethers, amides, alcohols and glycol ethers. In someembodiments, the solvent compound is selected from ethylene glycolmonopropyl ether, diethylene glycol mono butyl ether, ethylene glycolmono 2-ethylhexyl ether, DMF, THF, propanol, and ethanol. In someembodiments, the solvent compound is selected from ethylene glycolmonopropyl ether, diethylene glycol mono butyl ether or ethylene glycolmono 2-ethylhexyl ether. Embodiments also exist with any one of theforegoing single compounds as a solvent.

Combinations in the Concentrated Antioxidant Solutions

The invention provides for a variety of component selections that allowthe delivery of significantly higher concentrations of phenolicantioxidants along with metal chelators. The invention thus includescombinations of the foregoing components to provide concentratedantioxidant solutions. The present invention allows preparation ofsolutions having high concentrations of phenolic antioxidants, even inthe presence of metal chelating compounds. The amount of phenolicantioxidant present in the concentrate solution may be in any desirablerange. Some examples include about 10 to about 90 weight %, about 20 toabout 90 weight %, about 25 to about 50 weight %, about 22 to about 50weight %, about 22 to about 40 weight %, about 20 to about 40 weight %,about 20 to about 30 weight %, about 25 to about 40 weight %, about 15to about 40 weight %, about 15 to about 30 weight %, and about 30 toabout 90 weight %, in each case based on the total weight ofconcentrated solution. Other examples include at least about 15%,greater than 21%, at least about 22%, at least about 23%, at least about24%, at least about 25%, at least about 30% and at least about 40%.Similarly the amount of metal chelating compound present in theconcentrate solution may be in any desirable range. Some examplesinclude about 0.1 to about 10 weight %, about 20 to about 90 weight %,about 25 to about 50 weight %, about 22 to about 50 weight %, about 22to about 40 weight %, about 20 to about 40 weight %, about 20 to about30 weight %, about 25 to about 40 weight %, about 15 to about 40 weight%, about 15 to about 30 weight %, and about 30 to about 90 weight %, ineach case based on the total weight of concentrated solution. Otherexamples include at least about 15%, greater than 21%, at least about22%, at least about 23%, at least about 24%, at least about 25%, atleast about 30% and at least about 40%. Where the metal chelatingcompound is present, it will be present in amounts of at least about0.5%. Embodiments exist with the above ranges of antioxidantconcentrations and several different concentrations of the metalchelating compound, including, for example, about 0.5 to about 20 weight%, about 0.5 to about 10 weight %, about 0.5 to about 5 weight %, 0.5 toabout 3 weight % and about 1.0 to about 3 weight %. Thus, for example,in some embodiments of the present invention, the antioxidantconcentrate comprises from about 25 to about 40 weight % of anantioxidant and from about 1 to about 3 weight % of a metal chelatingcompound. In some embodiments of the present invention, the antioxidantconcentrate comprises from about 25 to about 40 weight % of anantioxidant and from about 0.5 to about 10 weight % of a metal chelatingcompound. In some embodiments of the present invention, the antioxidantconcentrate comprises at least about 22% of an antioxidant and fromabout 0.5 to about 3 weight % of a metal chelating compound. In someembodiments of the present invention, the antioxidant concentratecomprises from about 15 to about 40 weight % of an antioxidant and fromabout 0.5 to about 10 weight %, optionally about 0.5 to about 5%, of ametal chelating compound while containing less than 10% of a surfaceactive agent.

In some embodiments, the antioxidant solution is readily miscible inbiodiesel. A readily miscible antioxidant solution is helpful because insome embodiments it allows the solution to become dissolved into thebiodiesel with little or no agitation or heating. Whether a solution is“readily miscible” in biodiesel is determined by the followingprocedure. A clear soy oil biodiesel having a yellowness index of 140based on ASTM Method E313-05 and containing no suspended particles orvisible internal phases is stored at room temperature for at least 24hours prior to the experiment. 20 grams of the biodiesel is placed intoan eight-dram, (1 fluid ounce, approximately 25 ml) screw-topcylindrical glass vial. 0.20 grams of the antioxidant solution to betested is then added and the vial is immediately sealed with a screw-topstopper and is inverted 180 degrees 5 times. After the fifth inversionthe vial is immediately inspected visually, first upright then on itsside for evidence of phase separation. If there is any separate phaselayer, suspended bodies or particles, haze, or globules of liquidadhering to the inner surface of glass vial, the solution is inverted upto an additional five times. The presence of any separate phase layer,suspended bodies or particles, haze, or globules of liquid adhering tothe inner surface of glass vial after 10 inversions indicates that thesolution is not “readily miscible” in biodiesel. The absence of all suchindicators indicates within 10 inversions or less indicates that thecomposition is “readily miscible” in biodiesel.

In some embodiments, the selection of components allows preparation of ahomogeneous composition that is readily miscible in biodiesel withoutthe use of surface active agents. Thus, in some embodiments, theinvention provides a homogeneous composition containing less than 10%total surface active agents by weight. As used throughout thisapplication, “surface active agents” means molecules that arecharacterized by the possession of both at least one hydrophilic group(polar or ionic) and at least one hydrophobic groups (containingstraight or branched chains of 10 or more unsaturated saturated orunsaturated carbons), and that reduce interfacial tension between twoliquids, or between liquids and solids. Some examples of surface activeagents include fatty acids, salts of fatty acids (e.g. soaps),aminoalcohols (C₁₀ and higher), long chain alcohols (C₁₀ and higher, andincluding long chain monoglycerides and diglycerides such as DIMODAN R/DK-A available from Danisco Cultor USA, Inc., New Century, Kans.), andethoxylated linear alcohols (e.g. TERGITOL 15-S series surfactantsavailable from DOW Chemical).

The type of solvent present in the concentrated antioxidant solution maybe selected from a single class of the above specified solvents or maybe a mixture of such solvents, depending upon the antioxidant, metalchelating compound, as well as the presence of other additives. Informulating the combinations of components, the solvent or solventcombination is chosen for the phenolic antioxidant and metal chelator inpart by taking account of the individual solubilities of the twocomponents. However, it has been found that in some embodiments thepresence of the phenolic antioxidant and the metal chelating compoundtogether should be properly considered rather than the individualsolubilities of the components. Some embodiments are amenable to singlesolvent systems. Multiple solvent systems may be used to improve thesolubilities of the system components or to modify the othercharacteristics of the solvent solution.

Glycol ethers (e.g. the C₂-C₁₅ glycol ethers such as Eastman DB solventor Eastman EP solvent) and amides (e.g. DMF) are suitable single solventsystems in many embodiments. Low molecular weight alcohols (C₁-C₃ orC₁-C₃) are useful in some embodiments, although combinations with othersolvents may be more useful for embodiments involving “hinderedphenols,” or phenolic antioxidants having a plurality branched or longchain alkyl groups, thereby limiting their solubility in the alcohols(e.g. BHT, which has two tert-butyl chains). Also, methanol's utility inbiodiesel may be limited due to product specifications.

In some embodiments involving hindered phenols in combination withchelators that are hydroxycarboxylic acids (e.g. citric acid),hydroxycarboxylic acid esters (e.g. triethyl citrate), or aminoalcohols(e.g. triethanolamine), glycol ethers (e.g. C₂-C₁₅ glycol ethers) andamide solvents are useful in forming single solvent systems. In someembodiments in which the chelator is a polyamine such asethylenediamine, ketones (e.g. C₃-C₁₄ ketones such as acetone), esters(e.g. C₃-C₁₅ esters such as ethyl acetate) nitro-compounds (e.g.nitrobenzene) or ethers (e.g. THF) are useful in achieving highersolubilities with hindered phenols.

In some embodiments in which the antioxidant is a mono-alkylateddiphenol (e.g. TBHQ) and the choice of chelator is a carboxylic acid(e.g. citric acid), glycol ethers (e.g. C₂-C₁₅ glycol ethers), alcohols(e.g. C₂-C₁₅ glycol ethers), or amides (e.g. DMF) can be used in singlesolvent systems. In some embodiments in which the antioxidant is amono-alkylated diphenol (e.g. TBHQ) and the choice of chelator is acarboxylic acid C₂-C₁₅ glycol ethers are used in single solvent systems.In some embodiments involving mono-alkylated diphenols and a chelatorselected from the classes of citric acid esters, aminoalcohols, ordiamines, more hydrophobic solvents such as ketones (e.g. C₃-C₁₄ketones), esters (e.g. C₃-C₁₅ esters,) or ethers (e.g. THF) are used insingle solvent systems.

In some embodiments, the phenolic antioxidant is a diphenol monoether(e.g. BHA), the chelator is selected from citric acid or its esters, andthe single solvent is a glycol ether (e.g. a C₂-C₁₅ glycol ether), anamide, or an alcohol. In some embodiments, the phenolic antioxidant is adiphenol monoether (e.g. BHA), the chelator is an aminoalcohol, and thesingle solvent is a nitro-compound (e.g. nitrobenzene). In someembodiments, the phenolic antioxidant is a diphenol monoether (e.g.BHA), the chelator is a polyamine and a multiple solvent system is used.

In some embodiments involving a phenolic antioxidant from the class oftriphenols (e.g. pyrogallol) and citric acid, a single solvent isselected from glycol ethers (e.g. C₂-C₁₅ glycol ethers), and amides(e.g. DMF). In some embodiments involving a triphenol antioxidant andesters of citric acid, the single solvent is selected from ketones (e.g.C₃-C₁₄ ketones), esters (e.g. C₃-C₁₅ esters,) and ethers (e.g. THF).

In some embodiments, the compositions have a flash point of higher than100 degrees Fahrenheit as determined using ASTM Method Number: D3828-05.This can be accomplished, for example, through selection of solvents orsolvent combinations that will result in a final composition having thedesired flashpoint. Achieving high solubility of phenolic antioxidantsin the presence of metal chelators, while maintaining miscibility inbiodiesel and a flash point above 100 degrees Fahrenheit, is one of theadvantages of some embodiments of this invention. In some embodiments,the composition is (i.e. does not precipitate and separate) stable atcold temperatures (e.g. −25 Degrees F. for seven days).

In some embodiments, the concentrated antioxidant solutions may furtherinclude specific functional additives, such as cold flow additives,biocides, engine cleaning agents, surface active agents,compatibilizers, and corrosion inhibitors. In some embodiments, suchadditives are present in the concentrated solution collectively in anamount of from about 0.001 to about 40 weight %, based on the totalweight of concentrated solution. In some embodiments, such additives arepresent collectively in an amount of from about 0.1 to about 20 weight%, based on the total weight of concentrated solution.

In some embodiments, biodiesel is used as an ester solvent in theantioxidant concentrate solutions. In some embodiments, the concentratesolution comprises from about 15 to about 40 weight % and optionallyfrom about 15 to about 25 weight %, of an antioxidant; from about 5 toabout 30 weight % and optionally from about 5 to about 15 weight % of aglycol solvent; from about 0.1 to about 10 weight % and optionally fromabout 1 to about 2 weight % of a metal chelating compound; from about 10to about 30 weight % of a surface active agent; and from about 30 toabout 60 weight % and optionally from about 40 to about 55 weight % ofbiodiesel.

Methods of Making Antioxidant Compositions

While the compositions of the present invention can be made by anymethod. the invention also includes methods of combining one or moresolvents, metal chelating compounds, and phenolic antioxidants. It hasbeen discovered that the order of combining the components can affectthe concentrations that can be achieved. In some embodiments, fullydissolving a metal chelating compound in a solvent before adding thephenolic antioxidant or combining with a solution containing thephenolic antioxidant results in preparations to which higherconcentrations of phenolic antioxidants can be added (without resultingin precipitation of the metal chelator or the phenolic antioxidant) ascompared to methods involving simultaneous addition of phenolicantioxidant and metal chelator, or addition of undissolved metalchelator to a solution already containing the phenolic antioxidant. Thishas been found, for example, in some embodiments in which the metalchelator and phenolic antioxidant have different solubilities.

Specifically, in some embodiments the metal chelating compound isdissolved in a solvent containing one or more compounds to form a firstsolution, which is then admixed with either the phenolic antioxidant ora second solution containing one or more solvent compounds and thephenolic antioxidant. Other solvent compounds and additives can beoptionally combined with the first solution before, during, or after thecombination with the phenolic antioxidant or second solution.

In some embodiments, a first solution is prepared containing a phenolicantioxidant in a solvent containing one or more compounds. A secondsolution is prepared containing a metal chelating compound in one ormore solvent compounds. Then a predetermined amount of the secondsolution is added to the first solution to give a third or finalsolution having the desired amounts of the antioxidant and metalchelating compound in a solution matrix. Optionally, the first or secondsolution, or both solutions, are combined with additional solventcompounds prior to mixing with each other.

In some embodiments, a metal chelating compound is first dissolved in asolvent containing one or more compounds to make a first solution. Oneor more additional solvent compounds is then added to the first solutionto form a solvent matrix having the metal chelating compound dissolvedin the solvent matrix. Then a phenolic antioxidant is added to thesolvent matrix to form the final concentrated solution having thedesired amounts of the antioxidant and metal chelating compound in asolution matrix.

In some embodiments, the metal chelating compound is added to a solventto make a solution. The phenolic antioxidant is then added to thesolution.

In each of the foregoing methods, the amounts of each component includedmay be predetermined such that the method produces any of the compoundsof the present invention. Thus, embodiments of the foregoing methodexist for each composition of the present invention.

In some embodiments, the components are miscible at room temperature. Insome embodiments, it may be appropriate to heat one or more of theprecursor solutions to achieve complete dissolution of the solute in thesolvent. In some embodiments, the solvent is heated to a temperature ofless than about 100° C. and optionally less than about 60° C.

Treated Compositions

The invention also provides fuel compositions that include all of thecomponents of at least one antioxidant concentrate solution of thepresent invention along with fatty acids or fatty acid esters (includingbiodiesel). Optionally, additional components may be added. In someembodiments of the present invention, the fuel composition contains from0.001 to 5 weight %, based on the weight of the composition, of anantioxidant concentrate solution of the present invention and has aconcentration of the phenolic antioxidant that is greater than about 5parts per million (ppm). In some embodiments of the present invention,the fuel composition contains from 0.001 to 1 weight % of theantioxidant concentrate solution based on the weight of the composition.In some embodiments of the present invention, the fuel compositioncontains from 0.001 to 0.4 weight % of the antioxidant concentratesolution based on the weight of the composition. In some embodiments,the treated composition contains between about 5 and about 1200 ppmphenolic antioxidant by weight. In some embodiments the treatedcomposition contains between about 5 and about 400 ppm phenolicantioxidant by weight. In some embodiments, the treated compositioncontains between about 30 and about 200 ppm phenolic antioxidant byweight.

The invention further provides fuel compositions that contain blends oftreated biodiesel and at least one other burnable fuel source. Thetreated biodiesel contains the antioxidant concentrate solution asdescribed in the preceding paragraph. As used herein, the term “burnablefuel source” means any fuel source that is capable of combustion andthat thermodynamically liberates heat upon combustion or oxidation. Someexamples of such burnable fuel sources include petroleum distillates,such as gasoline, petroleum diesel, and jet fuel; coal and coalslurries; natural gas; and hydrogen to name a few. In some embodiments,the burnable fuel source is a petroleum diesel fuel. In someembodiments, the treated biodiesel component of the blended fuel ispresent in an amount of at least about 2% by weight based on the totalweight of the blended fuel. Embodiments exist in which the treatedbiodiesel is at least about 5%, 10%, 20%, 30% or 50% based on the totalweight of the blended fuel. Embodiments also exist in which the treatedbiodiesel is present in a specified range of concentrations, such as1-10% by weight, 2-10% by weight 3-8% by weight, 10-20% by weight,15-25% by weight, or 20-30% by weight.

Uses of the Compositions

The present invention also includes methods of using the antioxidantconcentrate compositions of the present invention to increase theoxidative stability of with fatty acids or fatty acid esters (includingbiodiesel). In some embodiments, from about 0.001 to 5 weight % of theantioxidant concentrate solution is added, based on the overall weightof the treated composition. In some embodiments, the resultingconcentration of the antioxidant is greater than about 5 parts permillion (ppm), based on the weight of the treated composition. In someembodiments, the concentration of the metal chelating compound is fromabout 0.1 ppm to about 40 ppm, based on the weight of the treatedcomposition. In some embodiments, the treated composition containsbetween about 0.25 ppm and about 60 ppm metal chelating compound byweight. In some embodiments, the treated composition contains betweenabout 0.25 and about 20 ppm metal chelating compound by weight. In someembodiments, the treated composition contains between about 1.5 andabout 10 ppm metal chelating compound by weight. Any of the antioxidantconcentrate solutions of the present invention may be used in thismethod.

The present invention is illustrated in greater detail by the specificexamples presented below. It is to be understood that these examples areillustrative embodiments and are not intended to be limiting of theinvention, but rather are to be construed broadly within the scope andcontent of the appended claims. All parts and percentages in theexamples are on a weight basis unless otherwise stated.

EXAMPLES

Several mixtures containing phenolic antioxidants, metal chelatingcompounds and solvents were prepared. All combinations were prepared atroom temperature approximately 25° C. using one of eight modes ofpreparation, identified as “Prep Modes” in Table 1. “Antioxidant” refersto the phenolic antioxidant used and “Chelator” refers to the metalchelating compound used. All percentages are weight percentages based onthe final composition. “Prep Mode” 1 involved using a single solvent ina single vessel. Chelator was first dissolved in Solvent 1, after whichphenolic antioxidant was dissolved. “Prep Mode” 2 involved two solventsis a single vessel. Chelator was first dissolved in Solvent 1, followedby the addition of Solvent 2 immediately followed by phenolicantioxidant. “Prep Mode” 3 involved using two solvents and one vessel.Chelator was first dissolved in a mixture of Solvent 1 and Solvent 2,after which the phenolic antioxidant was added. “Prep Mode” 4 involvedusing two solvents and two vessels. Chelator was dissolved in Solvent 1in Vessel 1, and phenolic antioxidant was separately dissolved inSolvent 2 in Vessel 2. The separate solutions from Vessels 1 and 2 werethen combined. “Prep Mode” 5 involved using three solvents and onevessel. Chelator was dissolved in Solvent 1, followed by additions ofSolvent 2 and 3 (in no particular order, and immediately after oneanother), and then finally the phenolic antioxidant followed Solvents 2and 3. “Prep Mode” 6 involved three solvents and one vessel. Chelatorwas dissolved in mixture of Solvent 1 and Solvent 2. Solvent 3 was thenadded, followed immediately by the phenolic antioxidant. “Prep Mode” 7involved three solvents and two vessels. Chelator was dissolved in amixture of Solvent 1 and Solvent 2 in Vessel 1, Phenolic antioxidant wasdissolved in Solvent 3 in Vessel 2. The two solutions in Vessel 1 andVessel 2 were then combined. Some “Prep Mode” 6 and 7 examples did notinvolve the use of a chelator, so the solvent combinations mentioned didnot include chelators. “Prep Mode” 8 involved using a single solvent ina single vessel. Chelator and phenolic antioxidant were added to thesolvent immediately after each other (essentially simultaneously). Inthe above “Prep Mode” descriptions, addition of one componentimmediately after the other means that time was not taken to assurecomplete dissolution of the compound added first.

Samples 1-15 were prepared in ambient atmosphere; Examples 16 and upwere prepared under a nitrogen atmosphere. The solutions are presentedTable 1 below. Solutions were visually inspected after formulation.“Single Phase Soln” indicates whether the sample was free of evidence ofprecipitation of either phenolic antioxidant or metal chelator uponvisual inspection.

Some solutions were tested for cold storage stability, miscibility inbiodiesel or flashpoint (or a combination of them). Table 2 contains thedata from those tests. Where cold storage stability was tested, it wasdetermined as follows: Twenty grams of the antioxidant solution atambient temperature was weighed into an 8 dram vial. The vial was placedin a freezer at a temperature of −25 degrees Fahrenheit for seven days.The vials were then removed and visually inspected. Particulateformation, sedimentation, and/or phase separation was considered afailure. Solutions that passed are indicated “Y” in the “Storage Stable”column and solutions that failed are indicated “N.”

Whether a solution was considered miscible in biodiesel was determinedusing the test for determining whether the solution is “readily misciblein biodiesel” as defined herein. A clear soy oil biodiesel having ayellowness index of 140 based on ASTM Method E313-05 and containing nosuspended particles or visible internal phases was stored at roomtemperature for at least 24 hours prior to the experiment. 20 grams ofthe biodiesel was placed into an eight-dram, (1 fluid ounce,approximately 25 ml) screw-top cylindrical glass vial. 0.20 grams of theantioxidant solution to be tested was then added and the vial wasimmediately sealed with a screw-top stopper and was inverted 180 degrees5 times. After the fifth inversion the vial was immediately inspectedvisually, first upright then on its side for evidence of phaseseparation. If there was any separate phase layer, suspended bodies orparticles, haze, or globules of liquid adhering to the inner surface ofglass vial, the solution was inverted up to an additional five times.The presence of any separate phase layer, suspended bodies or particles,haze, or globules of liquid adhering to the inner surface of glass vialafter 10 inversions indicates that the solution was not “readilymiscible” in biodiesel. The absence of all such indicators indicateswithin 10 inversions or less indicates that the composition was “readilymiscible” in biodiesel. Solutions that were readily miscible areindicated “Y” under “Biodiesel Miscible” in Table 2 if such indicatorswere absent after only five inversions. For solutions in which theindicators were present after five inversions absent after anywhereabove five and up to 10 inversions, the number of inversions that wererequired to remove the indicators was noted. Solutions that were not“readily miscible are indicated “N.”

Flashpoint determinations were made using ASTM Method Number: D3828. Inall cases, the absence of data for a specific test in Table 2 indicatesthat the test in question was not performed.

TABLE 1 Single Example Prep Phase No. Antioxidant Chelator Solvent 1Solvent 2 Solvent 3 Mode Soln 1 TBHQ (20%) citric acid (1%) PM Acetate 1Y (79%) 2 TBHQ (30%) citric acid (1.5%) PM Acetate 1 Y (68.5) 3 TBHQ(40%) citric acid (2%) PM Acetate 1 Y (58%) 4 TBHQ (40%) citric acid(2%) PM Acetate 1 N (58%) 5 TBHQ (20%) citric acid (1%) PM Acetate 1 N(79%) 6 TBHQ (30%) citric acid (1.5%) PM Acetate Propylene 3 N (60%)Glycol (8.5%) 7 TBHQ (30%) citric acid (1.5%) C-11 (60%) Propylene 3 NGlycol (8.5%) 8 TBHQ (30%) citric acid (1.5%) KB-3 (60%) Propylene 3 NGlycol (8.5%) 9 TBHQ (30%) citric acid (1.5%) Propyl Propylene 3 NPropionate Glycol (8.5%) (60%) 10 TBHQ (30%) citric acid (1.5%) Ethanol1 N (68.5%) 11 TBHQ (30%) citric acid (1.5%) Ethanol KB-3 (50%) 3 N(18.5%) 12 TBHQ (30% citric acid (1.5%) Ethanol C-11 (50%) 3 N (18.5%)13 TBHQ (30%) citric acid (1.5%) Ethanol n-butyl acetate 3 Y (18.5%)(50%) 14 TBHQ (30%) citric acid (1.5%) THF (68.5%) 1 N 15 TBHQ (30%)citric acid (1.5%) DMF (68.5%) 1 Y 16 TBHQ (30%) citric acid (1.5%)Ethanol C-11 (50%) 3 N (18.5%) 17 TBHQ (30%) citric acid (1.5%) PMAcetate Propylene 3 N (60%) Glycol (8.5%) 18 TBHQ (30%) citric acid(1.5%) PM Acetate DMF (8.5%) 3 N (60%) 19 TBHQ (30%) citric acid (1.5%)PM Acetate DMF (8.5%) 3 N (60%) 20 t-butylcatechol citric acid (1.5%) PMAcetate Propylene 3 Y (30%) (60%) Glycol (8.5%) 21 TBHQ (30%) citricacid (1.5%) PM Acetate Biodiesel 2 N (27.7%) (40.8%) 22 TBHQ (30%)citric acid (1.5%) Ethanol Biodiesel 2 Y (27.7%) (40.8%) 23 2,6-di-t-citric acid (1.5%) Ethanol Biodiesel 2 butylphenol (27.7%) (40.8%) (25%)24 t-butylcatechol citric acid (1.5%) Ethanol Biodiesel 2 Y (30%)(27.7%) (40.8%) 25 TBHQ (30%) triethyl citrate Ethanol Biodiesel 2 Y(1.5%) (27.7%) (40.8%) 26 TBHQ (30%) N,N-disalicylidene- Propylene PMAcetate 2 N 1,2-propanediamine Glycol (8.5%) (60%) (1.5%) 27 Guaiacolcitric acid (1.5%) Propylene PM Acetate 2 Y (CTMME)(30%) Glycol (8.5%)(60%) 28 TBHQ (30%) Monostearyl PM Acetate Propylene 3 N Citrate (1.5%)(60%) Glycol (8.5%) 29 Propyl Gallate citric acid (1.5%) PM AcetatePropylene 3 N (30%) (60%) Glycol (8.5%) 30 Propyl Gallate citric acid(1.5%) Ethanol Biodiesel 2 N (30%) (27.7%) (40.8%) 31 Guaiacol citricacid (1.5%) Ethanol Biodiesel 2 Y (CTMME)(30%) (27.7%) (40.8%) 32 TBHQ(30%) triethylcitrate Propylene PM Acetate 2 Y (1.5%) Glycol (8.5%)(60%) 33 BHT (30%) citric acid (1.5%) Propylene PM Acetate 3 Glycol(8.5%) (60%) 34 DTBHQ (30%) citric acid (1.5%) PM Acetate Propylene 3 N(60%) Glycol (8.5%) 35 THQ (30%) citric acid (1.5%) Propylene PM Acetate3 N Glycol (8.5%) (60%) 36 Pyrogallol (30%) citric acid (1.5%) PropylenePM Acetate 3 Y Glycol (8.5%) (60%) 37 TBHQ (30%) citric acid (1.5%)Propylene PM Acetate 2 N Glycol (18.5%) (50%) 38 TBHQ (30%) citric acid(1.5%) Propylene PM Acetate Biodiesel 5 N Glycol (10%) (30%) (28.5%) 39TBHQ (30%) citric acid (1.5%) PM Acetate Biodiesel 2 N (38.5%) (30%) 40TBHQ (30%) citric acid (1.5%) Propylene PM Acetate Biodiesel 5 NGlycol(15%) (35%) (18.5%) 41 TBHQ (30%) Monostearyl Ethanol Biodiesel 2N Citrate (1.5%) (27.7%) (40.8%) 42 TBHQ (30%) N,N-disalicylidene-Ethanol Biodiesel 2 N 1,2-propanediamine (27.7%) (40.8%) (1.5%) 43 DOH(30%) citric acid (1.5%) Ethanol Biodiesel 2 N (27.7%) (40.8%) 44 DTBHQ(30%) citric acid (1.5%) Ethanol Biodiesel 2 N (27.7%) (40.8%) 45 HQ(30%) citric acid (1.5%) Ethanol Biodiesel 2 N (27.7%) (40.8%) 46 BHT(30%) citric acid (1.5%) Ethanol Biodiesel 2 N (27.7%) (40.8%) 47Catechol (30%) citric acid (1.5%) Ethanol Biodiesel 2 N (27.7%) (40.8%)48 HQMME (30%) citric acid (1.5%) Ethanol Biodiesel 2 N (27.7%) (40.8%)49 THQ (30%) citric acid (1.5%) Ethanol Biodiesel 2 N (27.7%) (40.8%) 50Pyrogallol (30%) citric acid (1.5%) Ethanol Biodiesel 2 N (27.7%)(40.8%) 51 BHA (30%) citric acid (1.5%) Ethanol Biodiesel 2 N (27.7%)(40.8%) 52 DOH (30%) citric acid (1.5%) Propylene PM Acetate 2 N Glycol(8.5%) (60%) 53 Catechol (30%) citric acid (1.5%) Propylene PM Acetate 2N Glycol (8.5%) (60%) 54 HQ (30%) citric acid (1.5%) Propylene PMAcetate 2 N Glycol (8.5%) (60%) 55 HQMME (30%) citric acid (1.5%)Propylene PM Acetate 2 Glycol (8.5%) (60%) 56 BHA (30%) citric acid(1.5%) Propylene PM Acetate 2 N Glycol (8.5%) (60%) 57 TBHQ (30%) citricacid (1.5%) Propylene PM Acetate Biodiesel 5 N Glycol (20%) (40%) (8.5%)58 TBHQ (24%)/ citric acid (1.5%) Propylene PM Acetate 5 Y DTBHQ (6%)Glycol (8.5%) (60%) 59 TBHQ (18%)/ citric acid (1.5%) Propylene PMAcetate 2 Y DTBHQ (12%) Glycol (8.5%) (60%) 60 TBHQ (24%)/ citric acid(1.5%) Ethanol Biodiesel 2 N DTBHQ (6%) (27.7%) (40.8%) 61 TBHQ (18%)/citric acid (1.5%) Ethanol Biodiesel 2 N DTBHQ (12%) (27.7%) (40.8%) 62TBHQ (30%) citric acid (1.5%) Propylene n-butylacetate 2 Y Glycol(18.5%) (50%) 63 TBHQ (30%) citric acid Propylene n-butylacetate 2 N(1.5%) Glycol (16.5%) (52%) 64 TBHQ (30%) citric acid Propylenen-butylacetate 2 N (1.5%) Glycol (13.5%) (55%) 65 TBHQ (30%) citric acidPropylene n-butylacetate 2 N (1.5%) Glycol (11%) (57.5%) 66 TBHQ (30%)citric acid Propylene n-butylacetate 2 N (1.5%) Glycol (8.5%) (60%) 67HQ (30%) citric acid Isopropanol 1 N (1.5%) (68.5%) 68 Propyl Gallatecitric acid Isopropanol 1 N (30%) (1.5%) (68.5%) 69 DTBHQ (30%) citricacid Isopropanol 1 N (1.5%) (68.5%) 70 HQ (30%) citric acid Acetone 1 N(1.5%) (68.5%) 71 Propyl Gallate citric acid Acetone 1 N (30%) (1.5%)(68.5%) 72 DTBHQ (30%) citric acid Acetone 1 N (1.5%) (68.5%) 73 HQ(20%) citric acid (1%) Isopropanol 1 N (79%) 74 DTBHQ (20%) citric acid(1%) Isopropanol 1 N (79%) 75 TBHQ (30%) citric acid Propylene PMAcetate 2 N (1.5%) Glycol (15%) (53.5%) 76 TBHQ (30%) MonostearylPropylene n-butylacetate 2 N Citrate (1.5%) Glycol (18.5%) (50%) 77 TBHQ(30%) Monostearyl Biodiesel n-butylacetate 2 N Citrate (1.5%) (18.5%)(50%) 78 TBHQ (30%) citric acid Propylene n-butylacetate 2 N (1.5%)Glycol (15%) (53.5%) 79 TBHQ (30%) citric acid Propylene methyl acetate2 N (1.5%) Glycol (16.5%) (52%) 80 TBHQ (30%) citric acid DMF (15%)n-butylacetate 2 N (1.5%) (53.5%) 81 TBHQ (30%) citric acid Ethanol(15%) n-butylacetate 2 N (1.5%) (53.5%) 82 TBHQ (30%) citric acid PMAcetate n-butylacetate 2 N (1.5%) (15%) (53.5%) 83 TBHQ (30%) citricacid THF (15%) n-butylacetate 2 N (1.5%) (53.5%) 84 TBHQ (30%) citricacid Isopropanol n-butylacetate 2 N (1.5%) (15%) (53.5%) 85 TBHQ (30%)citric acid Propylene EP Solvent 2 Y (1.5%) Glycol (15%) (53.5%) 86 TBHQ(30%) citric acid Propylene DM Solvent 2 Y (1.5%) Glycol (15%) (53.5%)87 TBHQ (30%) citric acid Propylene EB Solvent 2 Y (1.5%) Glycol (15%)(53.5%) 88 TBHQ (30%) citric acid EB Solvent n-butylacetate 2 N (1.5%)(15%) (53.5%) 89 TBHQ (30%) citric acid Propylene Isopropanol 2 N (1.5%)Glycol (15%) (53.5%) 90 TBHQ (30%) citric acid EB Solvent Isopropanol 2N (1.5%) (15%) (53.5%) 91 TBHQ (30%) citric acid PM Acetaten-butylacetate 4 N (1.5%) (18.5%) (50%) 92 TBHQ (30%) citric acid PMAcetate DMF (4%) n-butylacetate 7 N (1.5%) (11%) (53.5%) 93 TBHQ (18%)/citric acid Propylene n-butylacetate 4 N DTBHQ (12%) (1.5%) Glycol (15%)(53.5%) 94 TBHQ (18%)/ citric acid DB Solvent DMF (4%) n-butylacetate 7N DTBHQ (12%) (1.5%) (11%) (53.5%) 95 TBHQ (30%) citric acid PM AcetateIsopropanol n-butylacetate 7 N (1.5%) (11%) (4%) (53.5%) 96 TBHQ (30%)citric acid DB Solvent Isopropanol n-butylacetate 7 N (1.5%) (11%) (4%)(53.5%) 97 TBHQ (30%) citric acid Propylene Isopropanol n-butylacetate 7N (1.5%) Glycol (11%) (4%) (53.5%) 98 TBHQ (30%) citric acid PropyleneDB Solvent 4 Y (1.5%) Glycol (15%) (53.5%) 99 TBHQ (30%) citric acidPropylene DB Solvent 4 Y (1.5%) Glycol (11%) (57.5%) 100 TBHQ (30%)citric acid Propylene DB Solvent 4 N (1.5%) Glycol (7%) (61.5%) 101 TBHQ(30%) citric acid Propylene DB Solvent n-butylacetate 7 Y (1.5%) Glycol(11%) (4%) (53.5%) 102 TBHQ (30%) citric acid DB Solvent Propylenen-butylacetate 7 Y (1.5%) (8%) Glycol (7%) (53.5%) 103 TBHQ (30%) citricacid EP Solvent Propylene n-butylacetate 7 N (1.5%) (8%) Glycol (7%)(53.5%) 104 TBHQ (30%) citric acid DB Solvent Propylene n-butylacetate 7Y (1.5%) (8%) Glycol (7%) (53.5%) 105 BHT (30%) citric acid DB SolventPropylene n-butylacetate 7 Y (1.5%) (8%) Glycol (7%) (53.5%) 106 TBHQ(30%) citric acid DB Solvent Propylene n-butylacetate 7 Y (1.5%) (8%)Glycol (7%) (53.5%) 107 TBHQ (22.5%)/ citric acid DB Solvent Propylenen-butylacetate 7 Y DTBHQ (7.5%) (1.5%) (8%) Glycol (7%) (53.5%) 108 TBHQ(30%) citric acid DB Solvent Propylene n-butylacetate 7 Y (1.5%) (18%)Glycol (7%) (43.5%) 109 BHT (30%) citric acid DB Solvent Propylenen-butylacetate 7 N (1.5%) (8%) Glycol (7%) (53.5%) 110 BHT (30%) citricacid DB Solvent Propylene n-butylacetate 7 N (1.5%) (18%) Glycol (7%)(43.5%) 111 TBHQ (30%) citric acid DB Solvent Propylene n-butylacetate 7Y (1.5%) (43.5%) Glycol (7%) (18%) 112 TBHQ (30%) citric acid DB SolventPropylene n-butylacetate 7 Y (1.5%) (28%) Glycol (7%) (33.5%) 113 TBHQ(30%) citric acid DB Solvent Propylene n-butylacetate 7 Y (1.5%) (23%)Glycol (7%) (38.5%) 114 TBHQ (30%) citric acid DB Solvent Propylenen-butylacetate 7 Y (1.5%) (38%) Glycol (7%) (23.5%) 115 TBHQ (30%)citric acid (1%) DB Solvent Propylene n-butylacetate 7 Y (38%) Glycol(7%) (24%) 116 BHT (30%) citric acid Propylene PM Acetate 4 Y (1.5%)Glycol (8.5%) (60%) 117 TBHQ citric acid Propylene PM Acetate 4 Y(22.5%)/DTBHQ (1.5%) Glycol (8.5%) (60%) (7.5%) 118 BHT (30%) citricacid DB Solvent Propylene n-butylacetate 7 Y (1.5%) (38%) Glycol (7%)(23.5%) 119 TBHQ (22.5%)/ citric acid DB Solvent Propylenen-butylacetate 7 Y DTBHQ (7.5%) (1.5%) (38%) Glycol (7%) (23.5%) 120TBHQ (30%) citric acid DB Solvent Propylene MIBK (23.5%) 7 Y (1.5%)(38%) Glycol (7%) 121 TBHQ (30%) citric acid Propylene MIBK (53.5%) 4 Y(1.5%) Glycol (15%) 122 Propyl Gallate citric acid DB Solvent Propylenen-butylacetate 6 Y (30%) (1.5%) (38%) Glycol (7%) (23.5%) 123 HQ (30%)citric acid DB Solvent Propylene n-butylacetate 6 N (1.5%) (38%) Glycol(7%) (23.5%) 124 BKF (30%) citric acid DB Solvent Propylenen-butylacetate 6 Y (1.5%) (38%) Glycol (7%) (23.5%) 125 TBHQ (30%)citric acid DB Solvent Propylene 1-nitropropane 6 Y (1.5%) (38%) Glycol(7%) (23.5%) 126 TBHQ (30%) citric acid DB Solvent Propylene1-nitrobenzene 6 Y (1.5%) (38%) Glycol (7%) (23.5%) 127 TBHQ (30%)citric acid DB Solvent Decyl Alcohol n-butylacetate 6 Y (1.5%) (38%)(7%) (23.5%) 128 TBHQ (30%) citric acid DB Solvent Mixed Glycols-n-butylacetate 6 Y (1.5%) (38%) 90 (7%) (23.5%) 129 TBHQ (30%) citricacid DTE Solvent Propylene n-butylacetate 6 Y (1.5%) (38%) Glycol (7%)(23.5%) 130 TBHQ (30%) citric acid DTP Solvent Propylene n-butylacetate6 Y (1.5%) (38%) Glycol (7%) (23.5%) 131 TBHQ (30%) citric acid DPSolvent Propylene n-butylacetate 6 Y (1.5%) (38%) Glycol (7%) (23.5%)132 TBHQ (30%) DB Solvent Propylene n-butylacetate 6 Y (38%) Glycol (7%)(25%) 133 TBHQ (30%) citric acid DB Solvent PEG 400 (7%) n-butylacetate6 Y (1.5%) (38%) (23.5%) 134 TBHQ (30%) DB Solvent Decyl Alcoholn-butylacetate 6 Y (38%) (7%) (25%) 135 TBHQ (30%) citric acid DBSolvent Ethylene methyl acetate 6 Y (1.5%) (38%) Glycol (7%) (23.5%) 136TBHQ (30%) citric acid EEH Solvent 1-Octadecanol Biodiesel 6 N (1.5%)(38%) (7%) (23.5%) 137 Pyrogallol (30%) citric acid DB Solvent Propylenen-butylacetate 6 Y (1.5%) (38%) Glycol (7%) (23.5%) 138 BHA (30%) citricacid DB Solvent Propylene n-butylacetate 6 Y (1.5%) (38%) Glycol (7%)(23.5%) 139 TBHQ (30%) citric acid DB Solvent Propylene Acetone 6 Y(1.5%) (38%) Glycol (7%) (23.5%) 140 TBHQ (30%) citric acid PM SolventEthylene methyl acetate 6 Y (1.5%) (38%) Glycol (7%) (23.5%) 141 TBHQ(30%) citric acid EEH Solvent Propylene n-butylacetate 6 Y (1.5%) (38%)Glycol (7%) (23.5%) 142 TBHQ (30%) citric acid DB Solvent 1-Octadecanoln-butylacetate 6 N (1.5%) (38%) (7%) (23.5%) 143 THQ (30%) citric acidDB Solvent Propylene n-butylacetate 6 Y (1.5%) (38%) Glycol (7%) (23.5%)144 Catechol (30%) citric acid DB Solvent Propylene n-butylacetate 6 Y(1.5%) (38%) Glycol (7%) (23.5%) 145 Guaiacol (30%) citric acid DBSolvent Propylene n-butylacetate 6 Y (1.5%) (38%) Glycol (7%) (23.5%)146 TBHQ (30%) citric acid DB Solvent 2-Octyl-1- n-butylacetate 6 Y(1.5%) (38%) dodecanol (23.5%) (7%) 147 t-butylcatechol citric acid DBSolvent Propylene n-butylacetate 6 Y (30%) (1.5%) (38%) Glycol (7%)(23.5%) 148 2,6-Di-t- citric acid DB Solvent Propylene n-butylacetate 6Y butylphenol (1.5%) (38%) Glycol (7%) (23.5%) (30%) 149 HQMME (30%)citric acid DB Solvent Propylene n-butylacetate 6 Y (1.5%) (38%) Glycol(7%) (23.5%) 150 HQ (30%) DB Solvent Propylene n-butylacetate 6 N (38%)Glycol (7%) (25%) 151 BHA (30%) DB Solvent Propylene n-butylacetate 6 Y(38%) Glycol (7%) (25%) 152 Propyl Gallate DB Solvent Propylenen-butylacetate 6 Y (30%) (38%) Glycol (7%) (25%) 153 BHT (30%) DBSolvent Propylene n-butylacetate 6 Y (38%) Glycol (7%) (25%) 154 TBHQ(30%) citric acid DB Solvent 1 Y (1.5%) (68.5%) 155 TBHQ (30%) citricacid (1.5%) EP Solvent 1 Y (68.5%) 156 BHT (30%) citric acid (1.5%) DBSolvent 1 Y (68.5%) 157 BHT (30%) citric acid (1.5%) EP Solvent 1 Y(68.5%) 158 BHT (30%) citric acid (1.5%) PM Acetate 1 N (68.5%) 159 BHT(30%) citric acid (1.5%) DMF (68.5%) 1 Y 160 BHA (30%) citric acid(1.5%) DB Solvent 1 Y (68.5%) 161 BHA (30%) citric acid (1.5%) EPSolvent 1 Y (68.5%) 162 BHA (30%) citric acid (1.5%) PM Acetate 1 N(68.5%) 163 BHA (30%) citric acid (1.5%) DMF (68.5%) 1 Y 164 PropylGallate citric acid (1.5%) DB Solvent 1 Y (30%) (68.5%) 165 PropylGallate citric acid (1.5%) EP Solvent 1 N (30%) (68.5%) 166 PropylGallate citric acid (1.5%) PM Acetate 1 N (30%) (68.5%) 167 PropylGallate citric acid (1.5%) DMF (68.5%) 1 N (30%) 168 TBHQ (30%) citricacid (1.5%) Ethyl Acetate 1 N (68.5%) 169 TBHQ (30%) citric acid (1.5%)THF (68.5%) 1 N 170 TBHQ (30%) citric acid (1.5%) KB-3 (68.5%) 1 N 171TBHQ (30%) citric acid (1.5%) Nitrobenzene 1 N (68.5%) 172 TBHQ (30%)citric acid (1.5%) 1- 1 N Nitropropane (68.5%) 173 TBHQ (30%) citricacid (1.5%) n-butylacetate 1 N (68.5%) 174 TBHQ (30%) citric acid (1.5%)Isopropanol 1 N (68.5%) 175 Pyrogallol (30%) citric acid (1.5%) EPSolvent 1 Y (68.5%) 176 Pyrogallol (30%) citric acid (1.5%) DMF (68.5%)1 Y 177 TBHQ (30%) citric acid (1.5%) Acetone 1 N (68.5%) 178 TBHQ (30%)citric acid (1.5%) MAK (68.5%) 1 N 179 TBHQ (30%) ethylenediamine DMF(68.5%) 1 Y (1.5%) 180 TBHQ (30%) ethylenediamine Isopropanol 1 Y (1.5%)(68.5%) 181 TBHQ (30%) ethylenediamine EP Solvent 1 Y (1.5%) (68.5%) 182TBHQ (30%) triethyl citrate (1.5%) DMF (68.5%) 1 Y 183 TBHQ (30%)triethyl citrate (1.5%) Isopropanol 1 Y (68.5%) 184 TBHQ (30%) triethylcitrate (1.5%) EP Solvent 1 Y (68.5%) 185 BHA (30%) triethyl citrate(1.5%) DMF (68.5%) 1 Y 186 BHA (30%) triethyl citrate (1.5%) Isopropanol1 Y (68.5%) 187 BHA (30%) triethyl citrate (1.5%) EP Solvent 1 Y (68.5%)188 t-butylcatechol ethylenediamine DMF (68.5%) 1 Y (30%) (1.5%) 189t-butylcatechol ethylenediamine Isopropanol 1 N (30%) (1.5%) (68.5%) 190t-butylcatechol ethylenediamine EP Solvent 1 N (30%) (1.5%) (68.5%) 191t-butylcatechol triethyl citrate (1.5%) DMF (68.5%) 1 Y (30%) 192t-butylcatechol triethyl citrate (1.5%) Isopropanol 1 Y (30%) (68.5%)193 t-butylcatechol triethyl citrate (1.5%) EP Solvent 1 Y (30%) (68.5%)194 BHT (30%) ethylenediamine DMF (68.5%) 1 Y (1.5%) 195 BHT (30%)ethylenediamine Isopropanol 1 N (1.5%) (68.5%) 196 BHT (30%)ethylenediamine EP Solvent 1 Y (1.5%) (68.5%) 197 BHT (30%) triethylcitrate (1.5%) DMF (68.5%) 1 Y 198 BHT (30%) triethyl citrate (1.5%)Isopropanol 1 N (68.5%) 199 BHT (30%) triethyl citrate (1.5%) EP Solvent1 Y (68.5%) 200 BHA (30%) ethylenediamine DMF (68.5%) 1 N (1.5%) 201 BHA(30%) ethylenediamine Isopropanol 1 N (1.5%) (68.5%) 202 BHA (30%)ethylenediamine EP Solvent 1 N (1.5%) (68.5%) 203 TBHQ (25%)ethylenediamine Ethyl Acetate 1 Y (1.25%) (73.75%) 204 TBHQ (25%)ethylenediamine Acetone 1 Y (1.25%) (73.75%) 205 TBHQ (25%)ethylenediamine Nitrobenzene 1 N (1.25%) (73.75%) 206 TBHQ (25%)ethylenediamine THF (73.75%) 1 Y (1.25%) 207 BHT (25%) ethylenediamineEthyl Acetate 1 Y (1.25%) (73.75%) 208 BHT (25%) ethylenediamine Acetone1 Y (1.25%) (73.75%) 209 BHT (25%) ethylenediamine Nitrobenzene 1 Y(1.25%) (73.75%) 210 BHT (25%) ethylenediamine THF (73.75%) 1 Y (1.25%)211 TBHQ (25%) triethyl citrate (1.25%) Ethyl Acetate 1 Y (73.75%) 212TBHQ (25%) triethyl citrate (1.25%) Acetone 1 Y (73.75%) 213 TBHQ (25%)triethyl citrate (1.25%) Nitrobenzene 1 N (73.75%) 214 TBHQ (25%)triethyl citrate (1.25%) THF (73.75%) 1 Y 215 TBHQ (30%) triethanolamine(1.5%) DMF (68.5%) 1 Y 216 TBHQ (30%) triethanolamine (1.5%) Isopropanol1 Y (68.5%) 217 TBHQ (30%) triethanolamine (1.5%) EP Solvent 1 Y (68.5%)218 t-butylcatechol triethanolamine (1.5%) DMF (68.5%) 1 Y (30%) 219t-butylcatechol triethanolamine (1.5%) Isopropanol 1 Y (30%) (68.5%) 220t-butylcatechol triethanolamine (1.5%) EP Solvent 1 Y (30%) (68.5%) 221BHT (30%) triethanolamine (1.5%) DMF (68.5%) 1 Y 222 BHT (30%)triethanolamine (1.5%) Isopropanol 1 N (68.5%) 223 BHT (30%)triethanolamine (1.5%) EP Solvent 1 Y (68.5%) 224 BHA (30%)triethanolamine (1.5%) DMF (68.5%) 1 Y 225 BHA (30%) triethanolamine(1.5%) Isopropanol 1 Y (68.5%) 226 BHA (30%)) triethanolamine EP Solvent1 Y (1.5%) (68.5%) 227 TBHQ (25%) triethanolamine Ethyl Acetate 1 Y(1.25%) (73.75%) 228 TBHQ (25%) triethanolamine Acetone 1 Y (1.25%)(73.75%) 229 TBHQ (25%) triethanolamine Nitrobenzene 1 N (1.25%)(73.75%) 230 TBHQ (25%) triethanolamine THF (73.75%) 1 Y (1.25%) 231 BHA(25%) triethanolamine Ethyl Acetate 1 N (1.25%) (73.75%) 232 BHA (25%)triethanolamine Acetone 1 N (1.25%) (73.75%) 233 BHA (25%)triethanolamine Nitrobenzene 1 Y (1.25%) (73.75%) 234 BHA (25%)triethanolamine THF (73.75%) 1 N (1.25%) 235 Pyrogallol (25%) triethylcitrate (1.25%) Ethyl Acetate 1 Y (73.75%) 236 Pyrogallol (25%) triethylcitrate (1.25%) Acetone 1 Y (73.75%) 237 Pyrogallol (25%) triethylcitrate (1.25%) Nitrobenzene 1 N (73.75%) 238 Pyrogallol (25%) triethylcitrate (1.25%) THF (73.75%) 1 Y 239 Pyrogallol (30%) triethyl citrate(1.5%) DMF (68.5%) 1 Y 240 Pyrogallol (30%) triethyl citrate (1.5%)Isopropanol 1 Y (68.5%) 241 Pyrogallol (30%) triethyl citrate (1.5%) EPSolvent 1 Y (68.5%) 242 Pyrogallol (30%) ethylenediamine DMF (68.5%) 1 Y(1.5%) 243 Pyrogallol (30%) ethylenediamine Isopropanol 1 N (1.5%)(68.5%) 244 Pyrogallol (30%) ethylenediamine EP Solvent 1 Y (1.5%)(68.5%) 245 Pyrogallol (30%) triethanolamine (1.5%) DMF (68.5%) 1 Y 246Pyrogallol (30%) triethanolamine (1.5%) Isopropanol 1 Y (68.5%) 247Pyrogallol (30%) triethanolamine (1.5%) EP Solvent 1 Y (68.5%) 248 BHT(8%) Citric Acid (2%) Ethanol (90%) 8 Y 249 BHA (8%) Citric Acid (2%)Ethanol (90%) 8 Y 250 BHT (15%) Citric Acid (1.5%) Ethanol 8 Y (83.5%)251 BHA (15%) Citric Acid (1.5%) Ethanol 8 Y (83.5%) 252 BHT (30%)Citric Acid (1.5%) Ethanol 8 N (68.5%) 253 BHA (30%) Citric Acid (1.5%)Ethanol 8 Y (68.5%) 254 BHT (22.5%) Citric Acid (1.5%) Ethanol (76%) 8 N255 BHT (25%) Citric Acid (1.5%) Ethanol 8 N (73.5%) 256 t-butylcatecholDB Solvent Propylene n- 7 Y (30%) (38%) Glycol (7%) butylacetate (25%)257 TBHQ (30%) Citric Acid (0.5%) DB Solvent 1 Y (69.5%) 258 TBHQ (30%)Citric Acid (1.0%) DB Solvent 1 Y (69.0%) 259 Pyrogallol (30%) DBSolvent Propylene n- 7 Y (38%) Glycol (7%) butylacetate (25%) 260Pyrogallol (30%) Citric Acid (1.5%) Ethanol 1 Y (68.5%) 261 TBHQ (20%)Citric Acid (1.5%) Ethanol 1 Y (78.5%) 262 TBHQ (10%) Citric Acid (1.5%)Ethanol 1 Y (88.5%) 263 t-butylcatechol Citric Acid (1.5%) Isopropanol 1Y (30%) (68.5%) 264 t-butylcatechol Citric acid (1.5%) Ethanol 1 Y (30%)(68.5%)

C-11 and KB-3 were mixtures of ketone byproducts from certain ketoneprocesses.

TABLE 2 Cold Cold Example Storage Storage Biodiesel Number Eval. StableMiscible Flashpoint 106 35° C. (95° F.) 108 38° C. (100.4° F.) 111 Y Y Y49° C. (120.2° F.) 112 40° C. (104° F.) 113 39° C. (102.2° F.) 114 Y Y Y46° C. (114.8° F.) 118 Y Y Y 120 Y Y Y 121 Y N N 122 Y Y Y 124 Y 125 Y Y8 126 Y Y 10  127 Y Y Y 128 Y Y N 129 Y Y Y 130 Y Y 6 131 Y Y 7 132 Y YY 133 Y Y 7 134 Y Y Y 135 Y N N 137 Y Y Y 138 Y Y Y 139 Y Y 7 140 Y N N141 Y Y Y 143 Y Y 7 144 Y Y Y 145 Y Y Y 146 Y Y Y 147 Y Y Y 148 Y Y N149 Y Y Y 151 Y Y Y 153 Y Y Y 155 Y Y 6 156 Y Y Y 157 Y Y Y 159 Y Y Y160 Y Y Y 163 Y Y N 164 Y Y 9 175 Y Y Y 176 Y Y N 179 Y N N 180 Y N N181 Y Y Y 182 Y Y 7 185 Y Y Y 186 Y Y Y 187 Y Y Y 188 Y Y 6 191 Y Y Y192 Y Y Y 193 Y Y Y 194 Y N Y 196 Y N 197 Y N Y 199 Y N Y 203 Y N Y 204Y Y Y 206 Y Y Y 207 Y N 208 Y N 209 Y N 210 Y N 211 Y N 212 Y Y N 214 YN 215 Y Y Y 216 Y Y 6 217 Y Y Y 218 Y Y Y 220 Y N Y 221 Y N Y 222 Y Y Y223 Y Y Y 224 Y Y Y 225 Y Y Y 226 Y Y Y 227 Y N 228 Y Y Y 230 Y N 233 YN 8 235 Y Y Y 236 Y Y Y 238 Y Y Y 239 Y Y N 240 Y Y Y 241 Y Y Y 242 Y YN 244 Y N 245 Y Y N 246 Y N 247 Y Y N 248 Y Y Y 249 Y Y Y 250 Y Y Y 251Y Y Y 253 Y Y Y 260 Y Y Y 261 Y Y 7 262 Y Y 6 263 Y Y Y 264 Y Y Y

Oxidative Stability Testing

The oxidative stability of biodiesel was evaluated using the antioxidantsolution of Example 114 above. Biodiesel fuels were prepared using soyoil, tallow (lard), canola oil, cottonseed oil, sunflower oil, andrapeseed oil using methods known to those skilled in the art. Samples ofeach biodiesel were treated with 0.067% of the antioxidant solution. Thetreated sample and a control sample containing no antioxidant wereplaced on the Oxidative Stability Instrument, available from Omnion. Theoxidative stability was determined using the procedure from the EuropeanEN14112. Results show the effectiveness of the antioxidant solution ofExample 114 as compared to the control sample. The results are in Table6 below. The data show that significant improvement in the inductiontime, i.e., the amount of time it takes for the mixture to reach thepoint where the resistance to oxidation is overcome and oxidation of thebiodiesel rapidly accelerates.

TABLE 3 Oxidative Stability Index (EN14112) Induction Time (hours at110° C.) Type of Biodiesel Control (No antioxidant) 0.067 wt % Soy 5.9522.7 Tallow (Lard) 7.05 25.18 Canola 6.95 15.58 Cottonseed 4.9 12.43Sunflower 0.93 8.8 Rapeseed 5.15 13.73

Biodiesel prepared from transesterification of soybean oil withmethanol, then distilled, was used. The antioxidant/metal chelatingcompound solution was added at a loading of 0.067 weight percent, basedupon the weight of the biodiesel, and mixed on a magnetic stir plate atambient temperature for 20 minutes. The concentration of the antioxidantin the final test solution was 200 ppm and the metal chelating compoundwas 10 ppm. The oxidative stability was determined using the procedurefrom the European EN14112. Results are presented in Table 4.

TABLE 4 Example Reference OSI Number (Hrs. at 110° C) Control 0.35 246.25 35 6.7 22 6.9 27 0.4 23 1.35 26 3.9 36 10.0 31 0.4 32 2.85 33 2.3525 3.05

Another batch of biodiesel prepared from transesterification of soybeanoil with methanol, then distilled, was used. The antioxidant/metalchelating compound solution was added at a loading of 0.067 weightpercent, based upon the weight of the biodiesel, and mixed on a magneticstir plate at ambient temperature for 20 minutes. The concentration ofthe antioxidant in the final test solution was 200 ppm and the metalchelating compound was 10 ppm. The oxidative stability was determinedusing the procedure from the European EN14112. Results are presented inTable 5.

TABLE 5 Example Reference OSI Number* (Hrs. at 110° C.) Control 0.25 2562.35 147 4.15 188 3.4 193 2.25 220 2.5 151 2.05 161 2.25 226 2.5 187 2.0132 2.05 114 3.8 217 1.75 181 2.35 184 2.0 153 1.10 157 1.4 223 1.05 1961.10 199 1.05 259 6.5 175 7.15 247 6.75 241 6.65

Effect of Order of Addition on Solubility

Example 2 was duplicated except that Prep Mode 8 was used. Visibleprecipitation of one or more of the components occurred.

Example 114 was duplicated with a different order of combiningcomponents. All components were combined in immediate succession (i.e.without allowing time to dissolve one or more components. Visibleprecipitation of one or more of the components occurred.

Example 114 was again duplicated with yet a different order of combiningcomponents. The three solvents were first combined, then the TBHQ wasadded and completely dissolved therein. Visible precipitation of one ormore of the components occurred. These experiments show that order ofaddition affects solubility in some embodiments (though not all, as thesuccessfully dissolved Prep Mode 8 examples demonstrate).

Having described the invention in detail, those skilled in the art willappreciate that modifications may be made to the various aspects of theinvention without departing from the scope and spirit of the inventiondisclosed and described herein. It is, therefore, not intended that thescope of the invention be limited to the specific embodimentsillustrated and described but rather it is intended that the scope ofthe present invention be determined by the appended claims and theirequivalents.

1. A composition comprising: a) between about 25% and about 35% by weight of tert-butyl hydroquinone, b) between about 1.0% and about 3.0% by weight of citric acid, c) between about 35% and about 45% by weight of diethylene glycol monobutyl ether, d) between about 5% and about 10% by weight of propylene glycol, and e) between about 20% and about 30% by weight of n-butyl acetate.
 2. A composition comprising: a) from about 0.001 to about 5 weight % of an antioxidant composition, wherein the antioxidant composition is the composition of claim 1, and b) at least one fatty acid or ester of fatty acid.
 3. The composition of claim 2, wherein the at least one fatty acid or ester of fatty acids is biodiesel.
 4. The composition of claim 2, wherein the composition comprises at least about 90% by weight of the at least one ester of fatty acids.
 5. The composition of claim 2, wherein the composition comprises from 0.001 to 0.4 weight % of the antioxidant composition.
 6. A composition comprising: a) at least one burnable fuel source, and b) a biodiesel composition, wherein the biodiesel composition is the composition of claim
 3. 7. The composition of claim 6, wherein the at least one burnable fuel source comprises at least one petroleum distillate.
 8. The composition of claim 6, wherein the at least one burnable fuel source comprises petroleum diesel.
 9. The composition of claim 8, wherein the composition comprises at least about 2% by weight of the biodiesel composition.
 10. A method for increasing the oxidative stability of at least one fatty acid or ester of fatty acid, comprising combining the at least one fatty acid or ester of fatty acid with the composition of claim
 1. 11. The method of claim 10, wherein at least one fatty acid or ester of fatty acids is biodiesel.
 12. A composition comprising: a) between about 15% and about 35% by weight of tert-butyl hydroquinone, b) between about 1.0% and about 3.0% by weight of citric acid, c) between about 35% and about 45% by weight of diethylene glycol monobutyl ether, d) between about 5% and about 10% by weight of propylene glycol, and e) between about 20% and about 30% by weight of n-butyl acetate, wherein the composition comprises 0% to 10% by weight of total surface active agents.
 13. A composition comprising: a) from about 0.001 to about 5 weight % of an antioxidant composition, wherein the antioxidant composition is the composition of claim 12, and, b) at least one fatty acid or ester of fatty acid.
 14. The composition of claim 13, wherein the at least one fatty acid or ester of fatty acids is biodiesel.
 15. The composition of claim 14, wherein the composition comprises at least about 90% by weight of the at least one esters of fatty acids.
 16. The composition of claim 13, wherein the composition comprises from 0.001 to 0.4 weight % of the antioxidant composition.
 17. A composition comprising: a) at least one burnable fuel source, and b) a biodiesel composition, wherein the biodiesel composition is the composition of claim
 14. 18. The composition of claim 17, wherein the at least one burnable fuel source comprises at least one petroleum distillate.
 19. The composition of claim 17, wherein the at least one burnable fuel source comprises petroleum diesel.
 20. The composition of claim 19, wherein the composition comprises at least about 2% by weight of the biodiesel composition.
 21. A method for increasing the oxidative stability of at least one fatty acid or ester of fatty acid, comprising combining the at least one fatty acid or ester of fatty acid with the composition of claim
 12. 22. The method of claim 21, wherein at least one fatty acid or ester of fatty acids is biodiesel. 